Modbus-Rtu Transmission Format - Toshiba TOSVERT VF-FS1 Instruction Manual

5.1. MODBUS-RTU transmission format

MODBUS-RTU sends and receives binary data without a frame-synchronizing start code and de-
fines the blank time to recognize the start of a frame. MODBUS-RTU decides the data that is first
received subsequently as the first byte of a frame after a blank time for 3.5 bytes at the on-going
communication speed.
【Request format / Positive responce】
Inverter
(3.5bytes
No.
Blank)
1byte
1) Inverter No. (1 byte)
2) Command (1 byte)
Command
（Decimal）
3) Data (variable ｌength)
4) CRC (2 bytes)
【Negative responce】
Inverter
(3.5bytes No.
Blank)
1byte
Command
1byte
: Specify an inverter number between 0 and 247 (00H to F7H).
Command processing will be executed only broadcast communication "0" and with
those inverters that match set inverter numbers. Data will not be returned if "0"
(broadcast communication) and inverter numbers do not match. Don't use the
number between 248 to 255(F8H to FFH) for inverter option and shipment test.
: Set the command. Refer to section 5.1.5 from 5.1.1.
Function
Read
03
Block read
06
Write
16
16 Block write
43 Identification
: Set the data requested by command.
: Set generation results of CRC in the order of low to high numbers. For the
method to generate CRC, see "5.2. CRC Generation". Note that the setting se-
quence is reversal to that of others.
Command
Requested command
+ 80H
Data
variable ｌength
Reference
Reads the data with the specified
communication number.
Block read communication
(Inverter -> Computer)
Reads the data with the specified
communication number.
(RAM and EEPROM).
Block write communication
(Computer -> Inverter)
Reads the Inverter information
(manufactur , type format , software
version)
Error code
See "5.3. Error codes".
27
E6581393
CRC16
(3.5bytes
low high
Blank)
１byte １byte
Remarks
5.1.1
5.1.2
5.1.3.1
5.1.3.2
5.1.4
5.1.5
CRC16
(3.5bytes
low high
Blank)
１byte １byte